A 9.1 V battery is connected to a 6.2 pF parallel-plate capacitor. What is the magnitude of the charge on each plate?

Two devices with capacitances of 21.6 µF and 5.2 µF are each charged with separate 120 V power supplies. Calculate the total energy stored in the two capacitors.

The operating potential difference of a light bulb is 120 V. The power rating of the bulb is 45 W.

(a) Find the current in the bulb.
1 A
(b) Find the bulb’s resistance.
2

A circular parallel-plate capacitor with a spacing of 1.5 mm is charged to produce a uniform electric field with a strength of 3.2 106 N/C. What plate radius is required if the stored charge is -11.9 µC?
1 m

An electronic flash fires a blast of energy from a 804 µF capacitor into a xenon lamp. It recharges through a series resistor of 4.9 k. How long will it take to recharge 63% of its maximum charge?
1 s

A charged 603 µF capacitor is in series with an open switch and a 3.6 k resistor. If the switch is closed, how long will it take for the charge on the capacitor to decay down to 37% of its original value?
1 s

A resistor is placed in series with an uncharged 2.2 µF capacitor, and a 15.0 V battery is put across the two. If the current that immediately flows around the circuit is measured to be 10 µA, determine the resistance. What is the time constant of the circuit?
1 s

I’m looking for an electronic lock w/ keypad. I’m looking for something to open/close and electronic circuit (like to turn on/off a light bulb). I’ve searched all over the internet, only finding electronic DOOR locks (I don’t want to use these). I was hoping to find one that has 12 keys (0-9, #, Ӿ), an LED/LCD display (to show keys hit, open/close, or anything else), and 3 LED’s (they would be to indicate ELECTRICITY FLOWING, CORRECT, INCORRECT). Anyone know where I could find something like this? Thanks!

Any simple/precise answer to these questions will be appreciated. Thanks!
1. What is the basic equation for power (in terms of amps + ohms)?
2. What is the purpose of a resistor?
3. Which is a more efficient electronic circuit: parallel or series?
4. Why do scientists refer to current (I) as if it flows from positive to negative when, in actuality, electrons flow from negative to positive?
5. How are static friction coefficients calculated?
6. What is diffraction?
7. How are electric fields/magnetic fields created?
8. Do each of these fields induce a corresponding force?
9. What is the Law of Induction?
10. How does one change the magnetic field?
11. What is magnetic flux?
12. What is electric flux (if that even exists)?
13. How does flux affect Induction?
14. Is there a way kinetic energy (like a treadmill or stationary bike) could power a light bulb with electromagnetic induction?

A particular electronic-code lock provides over 500 billion combinations. Moreover, it can sustain an electric shock of 1.25 x 105V. Suppose this potential difference is applied across a series connection of the following resistors: 11.0kΩ, 34.0kΩ, and 215kΩ. What is the equivalent resistance for the circuit?

A light bulb in a camper’s flashlight is labeled 2.4V, 0.70A. Find a) the resistance of the light bulb, If three of these light bulbs are connected in parallel to a standard C size 1.5V battery, find both b) the equivalent resistance of the entire circuit, and c) the current.

Transrapid, the world’s first train using magnetic field levitation, is designed to glide 1.0 cm above the track at speeds of up to 450 km/h. Suppose a charged particle with a charge of 12 x 10-9C and a speed of 450 km/h moves at a right angle to a 2.4T magnetic field. What is the magnetic force acting on the particle?

what is the easiest and cheapest way to have, say a light bulb on a simple DC circuit, switch off after 5 minutes. What electronic component does this?